Search engines try to provide the most relevant responses to user questions. Unfortunately, many search engines return information that may be unrelated, or not directly related, to the question. For example, search engines may return any document containing words matching keywords in the question. The user has to then manually sort through each returned document in an attempt to identify information that may be relevant or answer the question. This “brute force” method is time consuming and often fails to locate the precise information sought in the question.
Current search engines try to help the user in their manual document search by ranking the returned documents. This ranking method may rank documents simply according to the number of words in the documents that match keywords in the query. At least one critical limitation with this keyword search technique is that the user may not necessarily input search terms needed by the search engine to locate the correct information. In addition, even appropriate keywords may also be associated with other documents unrelated to the information sought by the user.
Search engines have been developed that attempt to classify queries. For example, the search engine may try to associate different words in the search query with different information categories. The search engine then attempts to provide the user with responses associated with the identified information category.
A critical problem with these information retrieval schemes is that there are seemingly limitless ways in a natural language for a user to request for the same information. And as also mentioned above, the user may not necessarily enter, or even know, the best words or phrases for identifying the appropriate information. Accordingly, the search engine can only classify a very limited number of subject matters. Further, a large amount of human resources are required to keep these types of search engines up to date with new information categories that may develop over time. Thus, these “higher level” search engines have had only limited success providing responses to user questions.
The present invention addresses this and other problems associated with the prior art.